According to a study published in The Lancet simply testing oxygen levels in the bloodA fluid that transports oxygen and other substances through the body, made up of blood cells suspended in a liquid. is a more accurate ‘marker’ of heart defects in babies than anything else.

This test according to the British Heart Foundation could "make a real difference" as many cases go unnoticed. Congenital heart defects such as holes between chambers in the heart and valveA structure that allows fluid to flow in one direction only, preventing backflow. defects affect just under 1% of all babies. At the momentIn physics it is the tendency of a force to twist or rotate another object the tests are relatively inaccurate, complicated and expensive involving ultrasoundA diagnostic method in which very high frequency sound waves are passed into the body and the reflective echoes analysed to build a picture of the internal organs – or of the foetus in the uterus. during pregnancythe period from conception to birth and listening to the heart after birth. The reason why this is a useful additional test is because these babies who are affected with heart defects do not necessarily have visible symptoms. The test is already in routine use in some US states and there does seem to be broad agreement that there is now compelling data to support the diagnostic inclusion of ‘pulse oximetryA painless, non-invasive test involving a small gadget clipped to a finger tip that measures the amount of oxygen in the blood’ into the care regimen for babies.

For the study, doctors used devices known as ‘pulse oximeters’ to detect levels of oxygen in the blood. If the levels were too low, or varied between the hands and feet, more detailed examinations took place. The test takes less than five minutes and diagnosed 75% of the most serious abnormalities and when combined with the traditional methods, 92% of cases were detected. This is important as advances in surgery mean that some cases can be corrected, although some defects are inoperable.

The lead researcher at the University of Birmingham Dr Andrew Ewer, has called for the test to be adopted by hospitals across the UK.